Automatic switch



' June 24, 1930. v E. GRANAT 1,766,292

AUTOMATIC SWITCH Filed Feb. 8, 1927 3 Sheets-Sheet l June 24? 1.930. E. GRANAT' 1,766292 AUTOMATIC SWITCH Filed Feb. 8, 1927 3 Sheets-Sheet 2 June 24, 1 930. E. GRAN/w 1,756,292v

AUTOMATIC SWITCH Filed Feb. 8, 1927 3 Sheets-Sheet 3 Patented' .June 24, 1930 Umbral): STATES Y ELIE GRANAT, )Fl P AEIS, FRANCE, ASSIGNOR OF ONE-HALF TO COMPAGN1E- DES 'FORGES ET ACIER/IES LA MARTNE ET DHOMECO'URT, OF PARIS, 'FRANCE A AUTOMATIC SWITCH l Appli'eationiiea lFebruary 8,1927, seriai'no. 166,800, anain France March 29, 1926.

My invention has `for its object an improved switch adapted to break an electric circuit automatically when its voltage or intensity ofthe currentilowing through it rises above a given value or else through a distant hand-control.. My improved switch provides moreover1 for thev automatic closing of the circuit as soonjas' the cause which has produced theubreaking is suppressed, an. untimely closing being prevented as long as the said cause remains operative. My improved switchv comprises a' shaft bearing the movable contacts'and normally held in the position corresponding to the closed circuitby a lever bearing 'against a cam keyed c to the ksaid shaft. This lever can be released bya finger secured tothe armature of an electro-'magnet which is excited and attracts its., armature when the voltage or the intensityA increases beyond a given value or in any other suitable case. When the lever is thus released, a springwound round the contactfbearing shaft brings the latter to the position corresponding to the opening of the.

circuit. i

`The switch is cocked automatically by meansof a constantlyoscillating beam. Mo-

tion is imparted toA this beam either constantly or at least whilst the circuit to be controlled remains open by a servo-motor. To this beam is pivotally secured va catch normally held away from a cooking cam keyed to the switch-shaft. The catch engages this cam under the action of an independent pivoting finger whereby the beam willrotate the cam through the said catch to turn the switchsha'ft to its closed position in ,which it isl locked. At the next oscillation of the beam the catch comes against a tooth of the cam which pushes it back into its normal position, the pivoting finger being previously movedaside through the rotation of the cam. On the other hand the cooking device cannot work too early whilst the -electromagnet remains excited by the same cause, because the pivoting finger is locked outside the path of the catch by a part secured to the armature of the said electromagnet, which part isV moved aside when the said armature is in its position corresponding to the closed circuit.

When a sudden closing of the circuit is desired in view of protecting `the contacts against the effects of the arc which might i'iash in case of a slow closing, the' device may be modified by way of example in the following manner. The cooking cam is disposed on a secondary shaft and serves to bind a spring which acts on a third cam secured to the switchshaft and held in the position corresponding to the open circuit by a spring-urged lever. This lever is released only by a tooth of the cooking cam Awhen this cam arrives in its cooking position. Thus the spring previously tensioned by the rotation of the cam will suddenly, at this moment move the third cam and thereby bring the switch in its closed circuityposition.

0n appended drawings I have shown byA way of example two forms of executionr of my improved switch.

Figs. l and 2 are perspectiveI views cfa irst form of execution respectively in po?. sit-ions vcorresponding to the closed and' Vto the open circuit. Fig. 3 isv a detail of rthe cock device. Figs. 4, 5 and 6 are` explanatory diagrams of Iits working. Figs; 7 and 8 are perspective views of modified forms of the invention adapted to close the circuit suddenly shown respectively before and after cocking. v Figs. 9, l() and 11' are :showing the positions oi' the parts during the cocking operation. Y

The construction shown in Figs; l and 2 comprises mainly a switchv constituted by a shatA borne in bearings not shown and to which are secured the movable contacts 7, 7. These contacts closethe circuit in the usual manner by connecting kthe parts 8 and 8 and the parts 8 andl 8. The switchshaft bears at one of its endsthe cam l and is held in its closed position l) bythe lever i pivoting round a stationary spindle not shown and urged bythe spring 3 anchored by suitable means not shown againstk the cam l. This lever l bears against `the tumbler 5 described hereinbelow and urged by theV spring 6 against the lever. The

spring 2 secured at one end to the stationary part P and at the other to a point at t-he periphery of the cam 1 has a tendency to bring the shaft into the osition correspondin to the open circuit ig. 2).

e tumblen 5` is secured to the armature of the releasing electromagnet Ewhich is excited in case the intensity or voltage in the Vcircuit to be rotected increases beyond a givenvalue. This electromagnet can also be excited from a distant control part when it is desired to cut oi' the current.

It may be readily understood that the spring 2 is bound'as long as the tumbler 5 and the lever 4 are in the position` correspondin' to the closed circuit. This spring brings the switch in its open position (Fig. 2) by rotating the shaft yA in the direction of the arrow f as soon as the armature of the electromagnetE and the tumbler are rotated in the directionof the arrow f and Vcome into the position shown on Fig. 2 whereby the cam 1 is released. The current is thus suddenly cutoff as soon as the electromagnet is excited.

'The cock device comprises a beam 15 v pivotally secured on a shaft, arallel to shaft A, and not shown on the gures to which the cock motor M imparts an oscillating motion throu h the bevel pinions 20, 21, the worm 19, t e worm wheel 18 mounted on a suitable spindle not shown and the crank 16. A catch 12 is ivotally secured as at 17 on the,` beam and as two possible positions one oflwhich I will term the lower osition and the other the higher position. hen in its lower sition it engages a notch formed in cam -170 keyed to the end of the shaft A, whereas in the higher position it is moved away from the said cam. A lever 13 subjeoted to the action of spring 14 is pivotally secured to the beam and engages either of the notches 12, or 12" of the catch according as to whether the latter is in its higher'or its lower osition. A three legged part 10 is pivotal t? engaged on ka stationary axis shown iagrammatically at 10, and also has two positions. The leg 10 abuts against the rear of the catch 12 and serves to force the said catch into its lower position at which time it is out ofthe path `of the catch. The pivoting part is urged into its operative position by t e spring 11, but is allowed to coineinto it only when the circuit is open and the electromagnet E is no longer excited. When this. is the case the tooth a` ofthe cam rocking with shaft A releases the pivoting part 10 which was, for shaft in its circuit closing position, forced in its inoperative position bythe said tooth a.

The pivoting part moves then into its operative osition as soon as its lower leg is released y the elongated stop 9 controlled b the electroma et E so as to keep the pivoting part in its inoperative position as long as the electromagnet is excited. When Y the electromagnet is not excited the stop 9 returns to its inoperative position whereby the pivoting part comes into its operative position. p n

The eo'clng operationniay be easil understood by referring toI diagrams own on Figs. 4 to 6. When the current is broken through* the rotation of shaft A the pivoting partlO isf held as stated in its inoperative,L "tionf until the cause, which has actuated tmhafti l A has disappeared, thatis, as lon as the; electromagnet E is excited. When t. e latter" Yis no longer excited and the stop 9 is rotated, m

part 1Q comes Ain its operativeposition under the action of the springlil.' As the beam.- is constantly 'rocking the top of l0 isin fthe path of the catch 12,' the la fr? will, by abutting the former, be` y; caused to come into its erative Yositin (Fig. 4) and, continuing oscilla e, with' the beam whereupon it engages the notch,Y shown between the teeth@ 'and c on the cam,l By reason of the shape ofthe notehas soon n as the and catch 'move towards the'l right, the catch will ,push the cam clockwise into the position shown-on Fig. 5 wherein the main circuit is vclosed again and the, pivoting'part 10 forced back bythe pro-h Qi; jection `a on the cani into `its` inoperative: position. When the beam returns to Ythaiy left, the catch 12 does not act on the cani..4 l On the contrary the tooth holds the catch elevated. The lever 13 is 'forced out of the notch 12b, and enters notchwl2 whereupon' the catch is caused to occupy, with reference" to the beam, a position wherein it can cillate with they latter without contacting` with the cam. As the pivoting part 10 is" m5 inoperative it cannot actfan more on the catch 12 which continues ting without any action on the device. i

he above described device, provides perfect safety in o eration. However it may up in certain cases Ee inconvenient as the clos@u ing of the circuit is not sudden and that the arcs ignitedat the closure of the high ten sion circuits might hurt thecontacts. It is. possible in the case o f ahig'h tension circuit ,im to modify lthe apparatus as shown on Figs.l i 7 and 8. In this modified form of execution, the cam 17 is mounted on an intermediary I. shaft alined with shaft A and independent of it, the catch and the pivoting part work` 12a ing exactlyas in the receding case. The" difference resides in t at the cam 17 does not actuate the shaft A directl but binds the spring 22 which controls t e lcam 26 keyed to the switchshaft A. The ends 23 im' and 24 of a U-shaped lever are held by a spring 25 against the two cams 17 and 26.

The working is similar to that of the aboveddescribed ap aratus. When the cir- 17 and 9) the lever end 12o..

cuit is open (Figs.

24 abuts against the end of the projection o on the cam 26. When the catch 12 has rotated the cam 17 by a certain angle when the apparatus is to be cocked, the spring 22 is tensioned but the cam 26 is kept stationary by the lever end 211 until at the end of the movement the other lever end 23 comes against the projection e of the cam 17 (Fig.10). The level end 23 is thus raised together with the lever end 2li whereby the cam 26 is released; the cam 26 is thus urged by the spring 22 into its circuit breaking position (Fig. 11). It comes suddenly into this position and binds at the same time the spring 2 which is weaker than spring 22. The circuit is suddenly closed. When it is broken for any suitable cause, the cams 26 and 17 connected by the spring 22 are brought back together by the spring 2 into their circuit breaking position.

Evidently the `above described devices are only disclosed by way of example. For instance the beam may be actuated only during the periods wherein the main circuit is opened this being provided by suitable auxiliary contacts. Thus the circuit of the cocking motor might be closed by two contacts borne by the cooking cam whereby the independently fed auxiliary motor works only when the said cam is in the position shown on Fig. 2.

The releasing electromagnet may be replaced by any other suitable mechanical or electric device. ln a similar manner the auxiliaryV cooking motor might be replaced by asuitable electric or mechanical servo-motor.

. This servo-motor may be the shaft of the motor of the generator group feeding the circuit in which is inserted my improved protecting switch; the mechanical control of the cooking device may be provided through a magnetic clutch the circuit of which is closed only when the electromagnet E has released the switchshaft.

It should be noted that the apparatus can be controlled from a distance and be disposed at any suitable point. It can work with A. C. or D. C., with or without delay, the. delay being obtainable by any suitable mechanicalv or electric means.

The apparatus can be provided with release and cooking levers for hand operation in case of damage to the said apparatus or of the lack of feed current for the auxiliary motor, these levers should be disposed so as to be reached only in case of absolute necessity; they can" for instance be locked by means of a special key.

What claim is:

1. In a switch of the class described, the combination with a shaft, of means whereby the shaft is brought into its circuit breaking position when the energy of the current in the circuit passes above normal value, means constantly moving, at least while the shaft in its circuit breaking position and operating to release said shaft to its circuit closing position, and means whereby the moving means are rendered inoperative during the time the energy of the current in the circuit remains above its normal value.

2./In -a switch of the class described, the combination with a shaft, of an electra magnet adapted to be excited when the energy of the current in the circuit passes above normal value, means whereby the said electromagnet when excited serves to move the shaft into its circuit ,breaking position, a beam, means for causing said beam to oscillate constantly, a cam controlled by the shaft, a catch pivotally secured to the beam and adapted to assume two positions, in one of which it serves to act through the cam on the shaft in a direction to force the latter back into its circuit closing position, means for holding the cam in operative and inoperative positions, means for urging the catch to operative position, and means adapted to render the last mentioned means inoperative when the electromagnet is excited and when the shaft is in its circuit closing position. f

3. ln a switch of the class described, the combination with a shaft, of an electromagnet adapted to be excited when the energy of the current in the circuit passes above normal value, means whereby the said electromagnet, when excited, moves the shaft into its circuit breaking position, a beam, means for causing said beam to oscillate constantly, a cam controlled by the shaft, a catch pivotally secured to the beam adapted to assume two positions, in one of which it serves to act through the cam on the shaft in a direction to force the latter backlinto circuit closing position, means for holding the cam in operative and inoperative position, a pivotally mounted part movable into the path of movement of the catch to urge it into its operative position, a part controlled by the electromagnet and adapted to prevent the pivotally mounted part from moving into the path of the catch while the electromagnet is excited, means whereby the cam pushes the pivotally mounted part out of the path of movement of the catch when the shaft is in its circuit closing position, and means for urging the pivotally mounted part into the path of movement of the catch.

4. In a switch of the class described, the combination with a shaft, of an electromagnet adapted to be excited when the energy of the current in the circuit passes above normal value, means whereby said electro magnet, when excited, moves the shaft into its circuit closing position, a beam, means for causing said beam to oscillate constantly, a cam, elastic means adapted to transmit the rotation of the cam to the shaft, means Vfor rotating the shaft under the action of the elastic means only after a given angular rotation of the cam, a catch i-votally secured to the beam' and adapte to as sume two positions, Vin one` of which it serves to actthrough the cam on the shaft in a direction to force the latter back into its circular closing position, means for holding the cam in operative and inoperative io positions,`means for. urging the catch to its operative position, and means adapted to render the last mentioned means inoperative I during a period when the electromagnet is excited and when the shaft is in its circuit u closing position. f

In testimony whereof I aix my signature. t

ELIE GRANAT. 

